Stacked Power Device Capacitor Assembly for Low Stray Inductance

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Solution Overview

Problem

High stray inductance in the connection of support capacitors and power devices leads to issues such as loss and signal attenuation in vehicle circuit systems.

Innovation Solution

The power device and capacitor assembly design involves electrical connectors with opposite current directions, stacked configurations, and fusion welding to minimize stray inductance, using isolation sheets for insulation, and intermediate connectors for efficient connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the support capacitor and power device are electrically connected using conventional connection methods, then the electrical connection is established, but the stray inductance becomes high causing loss and signal attenuation

Engineering Contradiction:
Improvestability and anti-interference abilityVSAvoidstray inductance loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent transitions from a planar connection layout to a three-dimensional stacked configuration. The first and second electrical connection ends are arranged in different layers (first layer and second layer) with vertical stacking in the second direction, which is perpendicular to the first direction of current flow. This spatial dimensionality change reduces the loop area and minimizes stray inductance while maintaining electrical connection functionality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent utilizes the magnetic field interaction between oppositely directed currents to cancel out stray inductance. By setting the current direction in the first electrical connector opposite to that in the second electrical connector, the magnetic fields generated by these currents interact to reduce the overall stray inductance, converting the potential harmful effect of magnetic field interaction into a beneficial cancellation effect.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Loss of energy

If the first electrical connection end and second electrical connection end are stacked closely, then stray inductance is reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvestray inductanceVSAvoidpositioning accuracy of connection ends
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent introduces an intermediate connector as a mediator between the power device and the support capacitor. This intermediate connector provides a standardized interface that simplifies the connection process and reduces the direct positioning requirements between the power device and capacitor, thereby lowering manufacturing precision requirements while maintaining the stacked configuration benefits.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrical connection system is divided into separate modular components: the power device body, the first and second electrical connectors, and the support capacitor. This segmentation allows each component to be manufactured and assembled independently, reducing the cumulative positioning errors and simplifying the overall manufacturing process while maintaining the low-stray-inductance stacked configuration.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Reduces stray inductance, enhances stability and anti-interference ability, ensuring safety and performance of the vehicle's power system.

Implementation Method 1

a direction of current flowing through the first electrical connector is set to be opposite to a direction of current flowing through the second electrical connector

Methodology Applied
Scientific EffectAlternating magnetic field: Alternating Magnetic Field

Implementation Method 2

the alternating magnetic field generated on the first electrical connection end and the alternating magnetic field generated on the second electrical connection end can at least partially cancel each other out

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4679505A1Power device, capacitor, power device assembly and vehicle
Publication Date: 2026.01.14 BYD CO LTD
  • EP4679505A1 patent drawingFigure 1
  • EP4679505A1 patent drawingFigure 2
  • EP4679505A1 patent drawingFigure 3

AI summary

A power device, a capacitor, a power device assembly and a vehicle. The power device includes a power device body, a first electric connector and a second electric connector, wherein the first electric connector includes a first electric connection end extending from the power device body in a first direction; the second electric connector includes a second electric connection end extending from the power device body; the direction of current flowing through the first electric connector is set to be opposite to the direction of current flowing through the second electric connector; the first electric connection end and the second electric connection end are stacked in a second direction; and the second direction is perpendicular to the first direction.